TWI574053B - Reflective element and method for manufacturing the same - Google Patents

Description

Reflective element and method of manufacturing same Related application

The present application claims priority to U.S. Patent Application Serial No. 61/254,758, filed on Oct. 26, 2009.

Field of invention

The present invention relates to a plastic molded reflective element for automated optical inspection.

Background of the invention

Machines for automated optical inspection require a variety of reflective elements (such as mirrors) that must be highly accurate and highly reflective.

Common methods used today to make reflective elements for automated optical inspection include initial machining followed by diamond turning.

Diamond turning is a machining process that uses precision components of a computer numerically controlled (CNC) lathe with natural or synthetic diamond-cut cutting elements. This process is also known as single point diamond turning (SPDT). Diamond turning processes are widely used to make high quality non-spherical optical components from crystals, metals, acrylics and other materials. Optical components produced by diamond turning are used in optical assemblies for telescopes, TV projectors, missile guidance systems, scientific instruments, and numerous other systems and devices (see: www.wikipedia.org).

The diamond turning process provides very precise (micron or even nanometer accuracy) reflective elements with very highly reflective reflective surfaces.

The manufacturing process of this prior art is very expensive and very long. Only a few sellers in the world can produce such products.

Therefore, there is a need for a solution that produces reflective elements for automated optical inspection in an inexpensive and efficient manner.

summary

In accordance with an embodiment of the present invention, a method for fabricating a reflective element is provided, the method comprising: designing or accepting a design of the reflective element; creating a precision mold (micron and even nanometer precision) to be used in the fabrication of the reflective element Characterization, such as by a diamond turning process; molding the reflective element while using the precision mold; and coating the reflective element with a reflective coating.

The method can include molding a reflective element (such as a mirror assembly) having a mirror having an arched and elongated shape when viewed from the front, wherein the two mounting elements extend outwardly in parallel relationship with one another, wherein the mirror has The majority of the perimeter of the mirror is a concave surface and a convex surface that are parallel to each other, wherein the upper edge of the mirror terminates at a narrow tip.

The method can include a molded mirror assembly including elongated structural ribs extending from the convex surface of the mirror.

The method can include removing material from the mirror assembly after termination of molding.

The method can include coating the reflective coating with a protective coating.

The method can include loading the reflective element into an automated optical inspection machine.

The method can include performing optical inspection while using the reflective element.

The method can include creating the precise mold using a diamond turning process.

According to an embodiment of the invention, there is provided a reflective element, which may be a mirror assembly comprising a mirror having an arched shape and an elongated shape when viewed from the front, wherein the two mounting elements extend outwardly in parallel relationship with each other The two mirrors are substantially parallel to each other near the short edges of the mirror, wherein the mirror has a concave surface and a convex surface that are parallel to each other through a majority of the perimeter of the mirror, wherein the upper edge of the mirror terminates at a narrow tip.

The reflective element can include elongated structural ribs extending from the convex surface of the mirror.

Simple illustration

In the conclusion part of the specification of the present invention, it is specifically indicated and clearly claimed The subject matter of the present invention. However, the structure and method of the present invention, as well as the objects, features, and advantages thereof, may be best understood by referring to the following detailed description read in conjunction with the accompanying drawings.

1 is a front view of a mirror assembly according to an embodiment of the present invention; FIG. 2 is a rear view of a mirror assembly according to an embodiment of the present invention; and FIG. 3 is a view showing a mirror according to another embodiment of the present invention. a rear view; the fourth and fifth figures show a narrow tip of the first and second mirror assemblies and a side view thereof in accordance with an embodiment of the present invention; and FIG. 6 shows a manufacturing process according to an embodiment of the present invention. A method of automated optical inspection of reflective elements used in machinery; and Figure 7 shows a system for fabricating reflective elements for use in automated optical inspection machinery in accordance with an embodiment of the present invention.

Detailed description of the schema

It will be understood that for simplicity and clarity of illustration, the elements shown in the drawings are not necessarily in accordance with the true scale. For example, some components may be exaggerated in size relative to other components for clarity. Further, when considered appropriate, the component numbers in the various figures may be repeated to indicate corresponding or identical components.

In the following detailed description, numerous specific details are set forth However, it will be appreciated by those skilled in the art that the present invention may be practiced without these specific details. Other examples, known methods, procedures, and components are not described in detail so as not to obscure the invention.

The systems and methods disclosed herein enable the fabrication of reflective elements for automated optical inspection at low cost and with very high geometric accuracy (micron or even nanometer accuracy), as well as the fabrication of highly reflective mirror surfaces. In the disclosed system and method, a diamond turning process (or equivalent process, such as polishing) is applied only to a precise mold that is a negative of the reflective element and from which a plurality of reflective elements are fabricated. . Therefore, although accurate molds may still be quite expensive (even if this is not the case), the reflective elements are inexpensive and accurate.

For example, mirrors produced by conventional techniques may cost between 1800 and 2000 dollars per piece, whereas substantially identical mirrors made by the method proposed by the present invention may result in mirror manufacturing costs of 50-60$.

1 shows a front view of a reflective element, such as mirror assembly 100, in accordance with an embodiment of the present invention. Figure 2 shows a back view of a mirror assembly 100 in accordance with an embodiment of the present invention.

Mirror assembly 100 is a reflective element. It includes a mirror 102 that exhibits an arched shape and an elongated shape when viewed from the front. The mirror 102 is coated with a reflective material and has a very precise surface.

The length L of the mirror 102 along the longitudinal axis 104 is longer than the peripheral length PL of the mirror 102 along the horizontal axis 106. The two short opposing edges 108 and 110 of the mirror 102 are spatially separated by a length L.

The mirror assembly 100 also includes two mounting members 112 and 114 that extend outwardly in parallel with each other and are substantially parallel to the Z-axis. The two long edges (upper edge 128 and lower edge 130) of mirror 102 are spatially separated from perimeter length PL.

The distance between the concave surface 150 of the mirror 102 and the convex surface 152 of the mirror 102 defines the width of the mirror 102. The mirror 102 has a fixed width along most, if not all, of its perimeter length.

The upper edge 128 terminates at a narrow tip 140. The narrow tip 140 can be made separately from molding, but can also be made by grinding or other removal of material after the molding process. It is very difficult, if not impossible, to manufacture highly accurate narrow tips from molding, so commercial users are removing materials and this is a cost effective molding technique.

Figures 4 and 5 show the narrow tip 140 and its surroundings. A dashed line 160 extending from the narrow tip 140 shows the reflective element before the material is removed. Thus, the area 162 between the dashed line 160 and the edge 164 of the mirror assembly 100 shows the removed material. FIG. 4 also shows reflective layer 170 and protective layer 172, both on the top end of concave surface 150 of mirror 102.

Figure 1 shows mounting elements 112 and 114 containing vertical (or substantially vertical) portions numbered 116 and 118, respectively. Vertical portions 116 and 118 are followed by horizontal (or substantially horizontal) portions numbered 120 and 122, respectively.

The horizontal portions 120 and 122 include vertical holes 124 and 126 into which bolts or other securing elements can be inserted to lock the mirror assembly 100 to the structural elements of the automated optical inspection machine.

Each of the vertical portions 116 and 118 can contain an inner portion and an outer portion. The inner portion is spatially spaced less than the length L, so that the vertical portion is partially obscured by the mirror 102 when viewed from the front.

Figure 3 shows a back view of a mirror assembly 101 in accordance with another embodiment of the present invention. The mirror assembly 101 of FIG. 3 differs from the mirror assembly 100 of FIG. 2 in that the mirror assembly 100 of FIG. 2 further includes elongated structural ribs 180 extending from the convex surface 152 of the mirror 102. It is noted that the mirror assembly 100 can have other support elements.

Figure 6 shows a method 10 of fabricating a reflective element, such as a mirror, for automated optical inspection machinery, in accordance with an embodiment of the present invention. Note that similar processes can also be used to make reflective elements for other applications.

Method 10 begins with the design (or acceptance design) stage 12 of the reflective element (especially the design of the shape, but may also be the design of other parameters (such as materials)). It is noted that the reflective element can include a mounting element (such as an insert) to combine it with other components of the automated optical inspection machine. Stage 12 can include designing a mirror assembly (such as that shown in any of the foregoing figures).

After the design is completed, the method continues with stage 14 of creating a precise mold for the reflective element. Note that this stage can include generating for reflection A precision mold of the component, the surface of which is coated with a reflective material to form a reflective surface, such as concave surface 150 of mirror 102 of FIG. Accuracy is in the micron range, even in the nanometer range.

Stage 14 can include applying a diamond turning process to achieve a highly accurate mold.

Stage 14 is followed by stage 16 of molding, using a precision mold, and a plurality of reflective elements. Note that with a precision mold, it is possible to create a large number of reflective elements. Non-limiting examples of reflective elements that can be produced in stage 16 are shown in Figures 1-5. The molded material can be polycarbonate but other materials can also be used.

Stage 16 can include molding a reflective element comprising a mirror having an arched and elongated shape when viewed from the front, wherein the two mounting elements extend outwardly in parallel with each other and substantially adjacent each other near the two short edges of the mirror Parallel, wherein through most of the perimeter length of the mirror, the mirror has concave surfaces and convex surfaces that are parallel to each other, wherein the upper edge of the mirror terminates at a narrow tip. The mounting element can have a vertical (or substantially vertical) portion followed by a horizontal (or substantially horizontal) portion. The horizontal portion may include a vertical hole through which a bolt or other securing element is inserted to lock the mirror assembly to the structural elements of the automated optical inspection machine. The mirror assembly can include a support member, such as an elongated structural rib extending from the convex surface of the mirror.

Stage 16 is followed by stage 17, which removes material from the molded reflective element. This removal is shown in Figures 4 and 5.

Stage 18 After stage 16, stage 18 is a reflective element coated with a reflective coating (eg, deposited aluminum).

Figure 6 shows stage 18 followed by stage 20, which is a reflective surface that coats each shaped part with a protective coating (e.g., against environmental damage). The material forming the protective coating may be cerium oxide (SiO ₂ ).

Stage 20 is followed by stage 22, which is to load the reflective element into an automated optical inspection machine.

Stage 22 is followed by stage 24, which is an optical inspection using automated optical inspection machinery including reflective elements (eg, optical inspection of integrated circuits).

Stage 24 can include directing the beam toward the reflective element and reflecting the beam from the reflective element. The reflective element can be a component of an automated optical inspection mechanical illumination path or collection path (or two paths).

Figure 7 shows a system 700 for fabricating reflective elements for automated optical inspection machinery (or for other uses) in accordance with an embodiment of the present invention.

System 700 can include a mold creation unit 710 for creating a precision mold for a reflective element (eg, according to a CAD design).

System 700 includes a molding unit 720 that produces a plurality of reflective elements by using a precision mold. Note that a single precision mold can be used to make many reflective elements.

System 700 can further include a coating unit (not shown) that is coated with a reflective coating (eg, deposited aluminum) (reflective elements produced by molding unit 720) and that may be coated (eg, against environmental damage) The layers coat the reflective surfaces of the individual shaped parts.

According to an embodiment of the invention, system 700 can also include a combination unit 730 for loading reflective elements into an automated optical inspection machine. In mechanical, the combined automated optical inspection machinery (including the manufactured reflective element) can then be used for optical inspection (eg, optical inspection of integrated circuits).

It is noted that although these various units may be installed and/or operated in a physically adjacent manner, this need not necessarily be the case. Furthermore, although more than two of these units can be incorporated into a single automated optical inspection machine, this need not necessarily be the case.

It is noted that, in accordance with some embodiments of the invention, the reflective element can be used to shape (e.g., collect) light to illuminate the scanned object.

In accordance with an embodiment of the invention, more than one reflective element (made by system 700) may be used in the same automated optical inspection machine.

According to an embodiment of the invention, the reflective element can be used to evenly distribute light onto the scanned object.

As mentioned previously, all of the components in the prior art are manufactured from solid materials and must be subjected to a final and expensive stage (diamond turning) for each of them, but contrary to the prior art, in accordance with the present invention, the components are It is manufactured from a parent (mold) and only the mold must be manufactured in such an expensive process (for example, diamond turning). Moreover, in the prior art, the reflective article is part of a solid material, whereas contrary to conventional techniques, the reflective surface is a molded component having a coating, if desired, in accordance with the present invention.

While certain features of the invention have been shown and described herein, many modifications, substitutions Therefore, it is to be understood that the scope of the appended claims is intended to cover all such modifications and changes that fall within the true spirit of the invention.

10‧‧‧ method

12,14,16,18,20,22,24‧‧

100,101‧‧‧Mirror assembly

102‧‧‧Mirror

104‧‧‧ vertical axis

106‧‧‧ horizontal axis

108,110‧‧‧ edge

112,114‧‧‧Installation components

116,118‧‧‧Vertical

120, 122‧‧‧ horizontal

124,126‧‧‧Vertical holes

128‧‧‧ upper edge

130‧‧‧ lower edge

140‧‧‧ narrow tip

150‧‧‧ concave surface

152‧‧‧ convex surface

160‧‧‧dotted line

162‧‧‧Area

164‧‧‧ edge

170‧‧‧reflective layer

172‧‧‧Protective layer

180‧‧‧Structural ribs

700‧‧‧ system

710‧‧‧Mold creation unit

720‧‧‧Molding unit

730‧‧‧ combination unit

1 is a front view of a mirror assembly according to an embodiment of the present invention; FIG. 2 is a rear view of a mirror assembly according to an embodiment of the present invention; and FIG. 3 is a view showing a mirror according to another embodiment of the present invention. a rear view; the fourth and fifth figures show a narrow tip of the first and second mirror assemblies and a side view thereof in accordance with an embodiment of the present invention; and FIG. 6 shows a manufacturing process according to an embodiment of the present invention. A method of automated optical inspection of reflective elements used in machinery; and Figure 7 shows a system for fabricating reflective elements for use in automated optical inspection machinery in accordance with an embodiment of the present invention.

10‧‧‧ method

12,14,16,18,20,22,24‧‧

Claims (13)

A method for fabricating a reflective element, the method comprising the steps of: designing or receiving a design of a reflective element; creating a precision mold to be used in the manufacture of the reflective element; wherein the precision of the precision mold is at a few nanometers The reflective element is molded while the precision mold is being used; and a concave surface of the reflective element is coated with a reflective coating to provide a reflective element comprising the concave surface and two mounting elements, the concave The surface is coated by the reflective coating and the two mounting elements extend outwardly in parallel with each other at two short edges adjacent the concave surface. The method of claim 1, wherein the concave surface coated by the reflective coating forms a mirror having an arched and elongated shape when viewed from the front and having a mirror through Most of the perimeter length is a concave surface and a convex surface parallel to each other, wherein the upper edge of the mirror terminates at a narrow tip. The method of claim 1, wherein the concave surface coated by the reflective coating forms a mirror, and wherein the molding step comprises molding an elongated structural rib extending from a convex surface of the mirror. A method of claim 2, comprising removing material from the reflective element. The method of claim 1, comprising coating the reflective coating with a protective coating. The method of claim 1, comprising mounting the reflective element into an automated optical inspection machine. The method of claim 6 of the patent application, including the use of the reflective element, performs optical detection. The method of claim 1, wherein the precise mold is created by using a diamond turning process. A reflective element comprising a mirror having an arched shape and an elongated shape when viewed from the front, wherein the two mounting elements extend outwardly in parallel with each other and are substantially perpendicular to the mirror near the short edges of the mirror a longitudinal axis, wherein the mirror has a concave surface and a convex surface that are parallel to each other through a majority of the peripheral length of the mirror, wherein the upper edge of the mirror terminates at a narrow tip, wherein the two mounting elements and the mirror The concave and convex surfaces are fabricated by molding the plastic in a precision mold. A reflective element according to claim 9 of the invention, comprising an elongated structural rib extending from the convex surface of the mirror. A reflective element according to claim 9 of the invention, comprising a protective coating applied to one of the reflective coatings. The reflective element of claim 9, wherein the precision mold is produced by using a diamond turning process. A reflective element according to claim 9 wherein the precision of the precision mold is in the range of a few nanometers.